package com.learn;


public class leet21 {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if (l1 == null) {
            return l2;
        } else if (l2 == null) {
            return l1;
        } else if (l1.val < l2.val) {
            l1.next = mergeTwoLists(l1.next,l2);
            return l1;
        }else{
           l2.next=mergeTwoLists(l1,l2.next);
           return l2;
        }
    }
}
